Barrel cooling device



Feb. 24,'1942. T. DE PORT ErAL. 2,273,839

BARREL COOLING DEVICE File'd June 16, 1939 Patented Feb. 24, 19142 BARREL cooLiNc nevica Theophile de Port, New Carlisle, and Walter G.

McNeill, Dayton, Ohio Application June 1.6, 1939, Serial No. 279,404

Il Claims. (Cl. 853-14) (Granted under the act of March 3, 1883, as amended April 30, 1928; 370 0. G. 757) The invention described herein may be manufactured and-used by or for the Government for governmental purposes, without the payment to us of any royalty thereon.

This invention relates to an apparatus for cooling the barrel of a rapid firing automatic machine gun. The device is particularly adapted for cooling the barrel of a machine gun partially or practically entirely enclosed in the wing of an airplane. The inventive concept involves inducing and maintaining a ow of cooling uid around the barrel of the machine gun by locating the entrance portion of the fluid conveying means in a place of high pressure and the exit portion in a place of high velocity and relatively low pressure.

Another feature of the invention is to provide meansfor conducting the hot gases resulting from the firing oi the gun to the outside of the cooling device so that very little, if any, of the hot gases of explosion will be conveyed along the barrel. In the drawing:

Figure l is a cross-sectional view showing the invention applied to a gun mounted in an airplane wing;

Figure 2 is a cross-section taken along lines 2--2 of Figure l.; l

Figure 3 is a View similar to Figure l showing a modled form of the invention;

Figure 4 is another view similar to Figure l showing still another modification of the inven tion.

Referring to the embodiment of the invention as illustrated in Figures 1 and 2 of the drawing, l is a machine gun suitably mounted in the wing 2 of an airplane. The machine gun is, in this embodiment, of the recoiling barrel type in which the barrel l is slidably supported at the front thereof in bearing di. Itis to be understood, however, that this invention is adapted to be used with other types of guns. Adjacent the muzzle of the gun is a circumferentially enlarged portion constituting a drum or reservoir 5 having an entrance cone or cowling B formed with an opening i9. In order to induce cooling air into entrance. opening i9 at all possible angles of attack of the wing, the drum, Cowling and entrance i9 thereof are larger in diameter than sleeve ll. The drum is, in eiect, a reservoir since the velocity of cooling fluid is lower in the drum than in sleeve il. The drum 5 and cowling E are located in the wing at apoint of high pressure. Circumferentially positioned in the outside of the drum 5 and at the junction of the drum and Cowling are openings 'l for conveying the hot BE gases of explosion to th'e atmosphere and for re lieving gas pressure in the drum and cowling during firing. The drum 5 is of slightly smaller diameter than the Cowling at its junction with the cowling so that openings 'l will be rearwardly directed. A large portion of the gases 0f combustion emit from openings 8 in chamber 9 to impinge against and follow along cowling 6 to exit openings l where they discharge into the atmosphere. The device is primarily intended to operate to cool the barrel between firing bursts. During firing, the pressure 0f the explosive gases will counteract to a large extent, if not entirely, the air pressure at opening I9. During firing, the openings 'l serve to relieve the pressure in drum 5 and Cowling B.

Upon movement 0f the airplane, air is forced into drum. 5 through opening I9 in`cowling 6 and forces air through slots I0 in barrel jacket Il into the jacket and along the barrel. The air discharges from the barrel jacket through slots l2 leading into chamber I3 and passageway lll formed in member il 4to an exit opening i5 located in a portion of the Wing adjacent which the air velocity is high and the pressure consequently low. An exit .louvre i6 is provided at opening l5 and is constructed to be rearwardly located to further decrease the low pressure at exit opening i5.

In the modied form of construction, shown in Figure 3, the barrel jacket in Figure 1 is omitted, a bearing 2li being provided in drum 5a for slidably supporting the front end of the barrel 3a. Sleeve 18a, mounted in wing 2a, is integral with drum 5a, cowling 6a and a member lla leading to the cooling air discharge port. In this form of the invention, the major portion of the gases escaping from the barrel will rise to engage and follow along the Cowling 6a and discharge into the atmosphere through openings la.

In the modiiied form of the invention shown in Figure 4, the construction is similar to that shown in Figure l except that the Cowling has been omitted. The combustion gases discharged from ports 8b are conveyed by a peripheral passageway 22 to tube 23 from which they are discharged into the atmosphere as shown by arrows in Figure 4. Casing lb, having drum 5b integral therewith, is mounted in wing 2b. Barrel jacket lib snugly ts in casing I8b and has, as in Figure 1, air 'opening ib as Well as a bearing lb for slidably receiving the barrel.

It is obvious that changes and modifications may be made in the device that fall within the inventive concept. For instance, members 22 and adapted to be arranged adjacent a high pressure area of said member'and an exit portion adapted to be arranged adjacent a low pressure area of said member, a drum operatively connected to the said entrance portion of said sleeve, said drum having a major portion of larger diameter than said sleeve and a forwardly extending inwardly curved portion forming an entrance of smaller diameter than said drum, said drum having gas discharge openings therein at the junction of the said forwardly extending portion thereof with the said major portion thereof.

2. In a barrel cooling device of the class wherein a gun barrel is mounted on and substantially enclosed within a movable member constructed .and arranged to have high and low pressure areas when moving, the combination of a sleeve surrounding -and spaced a short distance from said barrel and extending along the major portion of the length thereof, said sleeve having a relatively short entrance portion .of enlarged diameter adapted to be arranged adjacent a high pressure area of'said member and an exit portion adapted to be arranged adjacent a low pressure area of said member, a cowling connected to and extendthereof, said sleeve having an entrance portion ing forwardly of said entrance portion.v said cowling curving inwardly to form an entrance opening smaller than said entrance portion, said cowling having openings rearwardly of said entrance opening for allowing gases of combustion from said barrel to escape to the atmosphere.

3. In a barrel cooling device of the class wherein a gun barrel is mounted on and substantially enclosed within a movable member constructed and arranged to have high and low pressure areas` when moving, the combination of asleeve surrounding and spaced a relatively short distance from said barrel and extending along the major portion of the length thereof, said sleeve having a relatively short entrance portion of enlarged diameter provided with an air inlet opening located adjacent a high pressure area of said member, said sleeve having an exit portion located adjacent a low pressure area o1 said member, said enlarged portion of said sleeve being provided with rearwardly directed gas discharge openings therein.

4. In a barrel cooling device of the class wherein a gun barrel is mounted on and substantially enclosed within a movable member'. constructed and arranged to have high and. low pressure areas when moving, the combination of a sleeve surrounding and spaced a relatively short distance from said barrel and extending along the major portion of the lengthther'eof, said sleeve having a relatively short entrance portion of enlarged'diameter provided with an air inlet opening located adjacent a high pressure area of said member, said sleeve having an exit portion located adjacent a low pressure area of said member, said sleeve being provided with gas collecting means intcriorly thereof, and means for conveying said collected gases exteriorly of said sleeve.

THEOPHILE ma: PORT.

WALTER G. McNEILL. 

